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Sunday, May 31, 2009

I'll never have to focus again...

In trying out my new quartz dielectric diagonal this weekend with my AT6RC, not only did I have to remove both 2" extensions, but with the focuser dialed all the way in and locked camera was in perfect focus! It seems to me that if the diagonal is simply a reflection plane at 90 degrees, then this must be all about the AT Ritchey-Chretien telescope design. Amazing. I've sent an email off to Astronomics to see if they or the manufacturer know if this was intentional.

I've attached a picture below if you're not sure what I'm talking about.

Messier 12 and 25

Okay, so 12,800 ASA was a bit over the top. I've settled down now, 3200 ASA with this new camera will work just fine and reduce some of the time it takes to collect the images. It appears that 180 frames would be a good goal for a DSO, giving me more exposure time in less time than the Rebel XT at 1600 ASA.

Here we have a fine globular cluster M12 and a bright open cluster M25. M12 would have had more frames, but I bumped into the mount (wandering around in the dark) and caused the subsequent images to shift over 30 arcminutes. Pooh.

Saturday, May 30, 2009

Messier 9 and 10

Both globular clusters shots, unguided 30 x 15 sec. JPEG frames at 12,800 ASA, noise reduction enabled. Roughly 7.5 minutes of exposure time.

With just a few more Messier shots, I will have the first 20 Messier objects captured! ...just another 60 or so to go.

New Camera and Messier 8, the Lagoon Nebula

The Canon Rebel T1i DSLR camera just arrived and I've been checking it out. The camera is capable of 12,800 ASA and even boasts double the pixel density from my Rebel XT! It now takes only 20 minutes to collect the same amount of unguided exposure it would normally take me 3 hours to collect, still using 15 second frames. Clearly, noise processing is different but my initial results seem very pleasing.

So, here is the Lagoon Nebula taken with the new Ritchey-Chretien telescope and camera.

Oh yeah, no amp glow either!! That's a relief.

Tuesday, May 26, 2009

Messier 6

Well, its getting better. This shot of M6 was taken with 243 x 15 second JPEG exposures, 1600 ASA, approximately 60 minutes of exposure. I've created a new border template for the images, too. Getting easier to align the scope, and tracking was good. Now, I need to start learning about vignetting, something I didn't have to deal with on the Newt.

Monday, May 25, 2009

Messier 14

Unguided 193 x 15 second frames, 1600 ASA. This globular cluster includes numerous variable stars, there was even a Nova here in 1938.

Had trouble with clouds during this shot, not as bright as would like, but it is 2 orders of magnitude less bright than M2.

Messier 2

Unguided 72 x 15 second frames, 1600 ASA, noise reduction enabled, stacked and stretched. This a photo of the globular cluster M2, one of the largest. This object is 37,500 light years away and comprises approximately 150,000 stars!

Always make sure the batteries are charged

Forgot to charge my second battery. Arrg. After waiting for it to recharge, my second shoot of the night (early morning) of M2 captured only 72 exposures before daylight crept in.

Sunday, May 24, 2009

Photo shoot commencing...

Cloud cover finally cleared my target area, calculator kicked off for 250 takes. Again, I hope the clouds stay away.

Second night out

Alright. Everything is tightened down, now. No rotating. No tension on any of the wired connections. No motion sickness tonight.

3-star alignment went well. Zeroed in precisely on Antares right afterward, centered in the crosshairs. Focusing proceeded quickly, 2 minutes this time. I also took the time to align the new 60mm piggybacked refractor. What an excellent short scope, the view was crystal clear with excellent contrast. I viewed M57 with both a 25mm high quality Plossl and one of my wide-view 5mm eyepieces. Fantastic.

I'm pursuing M14 tonight. Waiting for a few clouds to dissipate. Hope they stay away.

Setting up...

Well, attempted shooting Messier 3 last night with limited success. Dark night, mostly clear. It's been six months since my last outing...a little out of practice, I guess. Focusing took quite some time, as I soon learned to take shorter bright star exposures to focus on the diffraction lines. The visual acuity of this RC scope is impressive. It turns out that only a few 3-second 1600 ASA exposures is all that is needed to perform LCD-review focusing. Now I know.

Tried to get 250 frames, but could only use 147. Something else I learned is to make sure the heavy duty Crayford focuser is securely tightened. The focuser unit on this RC scope can be rotated 360 degrees at your pleasure, unless its not fully tightened then it rotates on its own. I also found that I had not made sure the camera 2" extension was tightened. It was loose, too. Sooooo, the meandering image began with exposure number 148, and continued to do with the rest of the exposures - watch the bouncing ball.

Below is the not so impressive image of M3 taken with only 147 exposures.

Saturday, May 23, 2009

First trial photo...

Here is a 30-second shot at 1600 ASA of Arcturus, this time no noise reduction enabled, and parameter settings cleared. In getting into focus, it struck me how crisp the diffraction lines were - like sabers. This is likely not perfect focus as the visual acuity of this new scope clearly exceeds the limits of my 8 MP camera. When they say the AT6RC is an astrograph, they're not kidding. Be forewarned, the AT6RC is not intended for visual observing. Both of the 2" extensions were necessary to achieve prime focus with the DSLR. Evaluating image with eyepiece required a barlow and extension...looked like a damn microscope mounted on the back of the telescope. Very glad I added the 60mm short, great for viewing and with a 2" compression adapter I'll play with the camera use on it, too.

After this I took several 30-second shots of M4 before clouds set in, so I could get some feel as to overall improvement on a short collection of exposures. Found that stars were consistently spherical. Still picked up perceptible tracking error at 30 seconds (expected), and I did notice coma in the lower left and part of lower center in the overall image. This suggests I need to check collimation. The coma is certainly no where near as bad as on the Newt. I'm really just being nit picky. The image is excellent.

Unfortunately, my attention was diverted by the increased amp glow captured in so little frames. Yikes. I mentioned in prior posts the increasing strength of the glow. It would seem reasonable to deduce that over time taking the length of exposures required for astrophotography are pushing the limits of this camera design. The battery unit and power supply are just too close and the sensor is not well isolated from the energy produced - the amp glow is "burning in" to the sensor.

For the record, this is the 10,152nd exposure taken with the Rebel XT. Guess, it is time for a new camera. Supposedly, the new Rebel designs have improved noise reduction and have eliminated amp glow. Therefore, I should get considerably much more life out of a new camera. The XT will work just fine consigned to normal day photography, and I have a lovely lens kit for it.

A little pricey, but I've decided to purchase the new Rebel T1i (body-only of, course). It jumps two generations in DIGIC processor technology, almost doubles the image density to 15.1 megapixels, doubles my gain to 3200 ASA, and includes HD movie capture. Curiously, the movie capture mode suggests I could take planetary images like the current webcam craze...with way better resolution.

Ok. I done spending money, now.

Thursday, May 21, 2009

The New Telescope is Ready!!

Excellent! Here are some pics of the new rig. We shall have a wake in honor of my venerable $380 6" Newt, for it served me well. I'll try to keep it in safe storage, as I expect my young daughter will be very interested to use it.

Check out the extensions I had to add for prime focus.

Sunday, May 17, 2009

New telescope on the way...and it is not the Vixen

Sorry, Vixen. Astronomy Technologies new line of Ritchey-Chretien astrographs has you beat! I placed my order tonight for the AT6RC from Astronomy Technologies along with a 66mm short tube refractor (sporting a 2" Crayford focuser) as another photographic platform.

The AT6RC is 6" f/9 true RC hyperbolic mirror design, with 1/12th wave BK-7 mirrors, and enhanced aluminum coatings for 96% transmissivity. Like the Vixen VC200L, the AT6RC mirrors are fixed, and focusing is external. Unlike the VC200L, this new RC scope is a true reflector, no optical lenses. For another $600 I could have gone for the larger 8" RC with dialectric coatings for 99%, but just couldn't bring myself to do it.

Should have some great experiences with this!

Saturday, May 16, 2009

I'm back...

Alrighty. After several months away dealing with life, I'm ready to kick off some nightly astronomical activities.

The telescope mount has been realigned, camera batteries charged and cooled, and I've upgraded to Nebulosity 2.

The dark sky is upon us, and I'm just waiting for the clouds to clear...